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Johns Hopkins researchers develop hand-held chlamydia test

Researchers at the Johns Hopkins University have developed a low-cost diagnostic tool, slightly larger than a coffee mug, that detects chlamydia within 30 minutes.

Scientists hope the apparatus, unofficially called mobiLab, will improve screening for the common and often symptomless sexually transmitted disease that, if left untreated, can cause permanent damage to a woman's reproductive system and lead to fatal ectopic pregnancies.


The prototype, developed by researchers in the Hopkins Department of Biomedical Engineering, is made of a disposable cartridge for a genital swab sample and a heating unit that incubates the DNA to facilitate a reaction. The test results are delivered to and processed by a mobile app on a smartphone connected to the battery-powered device.

MobiLab is "the first demonstration of a cellphone-based DNA test of chlamydia," said researcher Jeff Wang, a Hopkins mechanical and biomedical engineering professor.


The machine is 6 inches tall, weighs as much as two or three iPhones, and costs about $200 to manufacture, said Dong Jin Shin, a Hopkins doctoral candidate and researcher. Standard tests cost between $50 and $200 without insurance, Shin said, but the per-run cost of his platform would be $2.

Wang said the research behind the device, which has spanned a decade and is sponsored by the National Institutes of Health, was inspired by conversations with other Hopkins branches and an industry-wide push toward point-of-care testing, where patients are diagnosed during their doctor's visit instead of in a lab days later.

"We talk to more and more physicians in the School of Medicine and the hospital who often express interest in … tests of patient samples in doctor's offices," he said. "They want it to be fast, accurate and also easy to use."

MobiLab could have significant implications for Maryland, which has struggled in recent years with high rates of sexually transmitted diseases like chlamydia. The area including Baltimore, Columbia and Towson was among the top 20 metropolitan areas in the United States for prevalence of chlamydia in 2013, according to data from the Centers for Disease Control and Prevention

The rate of chlamydia infection has fluctuated in Baltimore City in the past decade but is more prevalent today than in was a decade ago, according to city and state health data. In 2004, there were 6,651 reported cases, a rate of 1,047 per 100,000 people. In 2014, there were 7,577 reported cases of chlamydia in the city, with a rate of 1,220 per 100,000 people.

And the numbers are even higher, according to Patrick Chaulk, assistant commissioner of the city Health Department's Bureau of HIV/ STD Services, because official numbers only reflect diagnosed patients.

"We're probably missing a third of them," he said.

Chaulk said mobiLab could help contain the hard-to-control STD.


"Chlamydia is a strange bug because it infrequently produces symptoms, so people don't go in to get tested for it," he said. "People have the opportunity to spread it to others without knowing it, and that's why a device like this would be quite helpful."

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MobiLab uses nucleic acid-based testing, which offers greater accuracy than traditional lab cultures, Shin said. In some currently available tests, poor sensitivity can lead to a failure to detect the target molecule and return a false negative result, he said.

Researchers tested mobiLab against the "gold standard" swab sample test and got the same 10 positive and 10 negative results.

Wang said the next step is a clinical trial, for which they are enrolling patients at Johns Hopkins Hospital.

While mobiLab hasn't been tested for infections other than chlamydia, Wang said it could be used to test for other DNA/RNA-based infections. They plan to extend the application of the device with an HIV test, which uses RNA-based detection, and sepsis, which is DNA-based, he said.

His long-term vision for the device is for it to be used at patients' homes, like an at-home pregnancy test, Wang said. It also could be used in areas of the world with limited medical access, he said.


"I know how much impact this kind of a tool can make for developing countries," Wang said.